The DMM Aero HMS is an affordable belay biner with a large internal radius which is kind on ropes. It's elongated shape is stable in the belay loop and minimizes chances of cross loading. The Aero HMS has several features which raise it above the competition. For a start it’s hot forged – a process that allows us a much greater degree of freedom in the design and manufacturing process. A product of this design is the extremely generous rope radius – a whopping 11.3mm! It is also a very strong biner, and while it might not be the lightest locker around, this extra bulk means greater resistance to wear and excellent heat dissipation – something you will appreciate on your next big abseil.